It seems that there are a lot of Win98 machines out there that will NOT work with the Linksys WMP54G wireless network card.
You can Google your head off about it and most of what you'll find is that it simply does not work. However, there are the occasional posts detailing that they have it working under Win98 as well as other systems. How odd?
The process goes something like this...
First off, DO NOT INSTALL THE PCI CARD YET!
Get the new drivers from Linksys
Install them by running the setup from the folder you just unzipped.
When the PC tells you to reboot, simply power off.
Remove the case and install the card
When you reboot, the computer will automatically finish installing what it needs to get the card functioning. It will then go straight into scanning for any nearby access points or other wireless bretheren.
If the process does NOT happen as above, then this is where the problem appears to be. The other Win98 PC I tried it on would sort of install it, and the closest I got to making anything happen was Windows telling me that "There may be a problem with your card....etc". Looking closer at the hardware revealed that although I had indeed installed the drivers many times, it would just NOT seem to take. Reinstall the drivers, all looks well. Nothing cooking with the card. Take a look, and Windows still wants to know, "Hey man, like totally install the drivers, will ya?"
You can see the card listed in your hardware but cannot make the drivers stick. No matter what version you use. So all in all, it seems to be a motherboard type of thing. Second (make that third as I tried on a completely different Linux box but could not get anywhere with that, but hey, it's Linux, thats greek for impossible, isn't it?) PC I used it was flawless and began to work ok. Although by now it was three in the morning, so I got no further than a half asleep celebration which consisted of lying on the floor surrounded in freshly knocked over case screws, being told by the kitten that at my age I was being pathetic and should go to bed now.
Looking through many posts about this card turned up a lot of people who seemed to crash their systems when this card was installed. Even WinXP, of which more people reported success, but still a healthy percentage cried about all of it. If I had known this before I tried it, I would not have bothered and gone with another brand. It seemed only luck that it worked with one of the motherboards I had.
May the force be with you.
Wrong motherboard and you're dead